1. Field of the Invention
The present invention relates to novel crystalline 1,2-ethanedisulfonic acid salts of a biphenyl compound which are expected to be useful as therapeutic agents for treating pulmonary disorders. This invention also relates to pharmaceutical compositions comprising such crystalline compounds or prepared from such crystalline compounds, processes and intermediates for preparing such crystalline compounds and methods of using such crystalline compounds to treat a pulmonary disorder.
2. State of the Art
Commonly-assigned U.S. patent application Ser. No. 10/779,157, filed on Feb. 13, 2004, disclose novel biphenyl compounds that are useful as therapeutic agents for treating pulmonary disorders, such as chronic obstructive pulmonary disease (COPD) and asthma. In particular, the compound, biphenyl-2-ylcarbamic acid 1-[2-(2-chloro-4-{[(R)-2-hydroxy-2-(8-hydroxy-2-oxo-1,2-dihydroquinolin-5-yl)ethylamino]methyl}-5-methoxyphenylcarbarnoyl)ethyl]piperidin-4-yl ester is specifically disclosed in these applications as possessing both muscarinic antagonist and β2 adrenergic receptor agonist activity. The chemical structure of biphenyl-2-ylcarbamic acid 1-[2-(2-chloro-4-{[(R)-2-hydroxy-2-(8-hydroxy-2-oxo-1,2-dihydroquinolin-5-yl)ethylamino]methyl}-5-methoxyphenylcarbamoyl)ethyl]piperidin-4-yl ester is represented by formula I:

Therapeutic agents useful for treating pulmonary disorders are advantageously administered directly into the respiratory tract by inhalation. In this regard, several types of pharmaceutical inhalation devices have been developed for administering therapeutic agents by inhalation including dry powder inhalers (DPI), metered-dose inhalers (MDI) and nebulizer inhalers. When preparing pharmaceutical compositions and formulations for use in such devices, it is highly desirable to have a crystalline form of the therapeutic agent that is neither hygroscopic nor deliquescent and which has a relatively high melting point (i.e. greater than about 150° C.) thereby allowing the material to be micronized without significant decomposition or loss of crystallinity.
No crystalline salt forms of the compound of formula I have been reported previously. Accordingly, a need exists for a stable, non-deliquescent crystalline salt form of the compound of formula I which has an acceptable level of hygroscopicity and a relatively high melting point.